Enterprise server and storage systems are deployed in business critical applications. As such, minimizing system downtime in the event of a component or subsystem failure is critical to minimizing financial impact to the enterprise. Thus, it is beneficial to aid a repair technician by providing a dedicated visual indicator associated with a failed component or subsystem, so that the component or subsystem, known as a “field replaceable unit” or “FRU”, can be quickly located and replaced. To avoid ambiguity and minimize the chance of the repair technician replacing the wrong FRU, it is beneficial to place the visual FRU indicator as physically close to the FRU as possible.
In today's server and storage systems, light emitting diodes (LEDs) are typically used as FRU indications. For example, in a storage array containing several hard drives, there may be a hard drive failure LED indicator associated with each hard drive visible to the service technician on the front panel of the array. When the host system device detects that a hard drive has failed, the host system device illuminates the associated failure LED so a service technician knows which hard drive to replace. However, in these systems, host power is required to energize the circuitry which will illuminate the LED.
In some systems, the FRU to be replaced may be embedded inside of a system or subsystem that needs to be removed from a host system device in order to gain physical access to the FRU. In these cases, it may not be possible to provide power to the FRU LED because the FRU and associated subassembly have been physically removed from the host system device, and as a result have lost the power connection to the host system device. Consequently, there is no power to illuminate the appropriate FRU LED.
In view of the above, a more effective way of locating a failed FRU, for example in a bank of FRUs, is needed. Furthermore, when a failed FRU is detached from its host power source, the FRU status information becomes lost and as such, a way of preserving the FRU status information when the power connection with the host system device is removed is needed.